When I was a grad student the only tuition benefits I got were (a) I was allowed to pay in-state tuition instead of out-of-state and (b) I didn't have to pay fees for things like the Athletic department; this ended up being about 25% cheaper than in-state undergrad. On paper, (a) was a huge benefit, but considering I lived there for seven years and paid state and local taxes the whole time, I'm not inclined to be too generous with that accounting.